Sign support base



FIG. 1 is an exploded isometric view of a sign support base showing mynew design;

FIG. 2 is an enlarged isometric view of an assembled version of FIG. 1with the sign support mounted in place to the support base and the toplid portion in place.

FIG. 3 is a front elevational view of FIG. 2, with the back elevationalview being the mirror image of the front.

FIG. 4 is a right side elevational view of FIG. 3, with the left sideelevational view being the mirror image of the right; and,

FIG. 5 is the top view of FIG. 3.

The broken lines in the drawings represent environment structure onlyand form no part of the claimed design.

The ornamental design for a sign support base, as shown and described.